PubMed Health⌕ Search

Biomedical subjects

T Kawara

Publications and source records attributed to T Kawara.

At least 19 recordsLinked to original sources
PubMed2001

Activation delay after premature stimulation in chronically diseased human myocardium relates to the architecture of interstitial fibrosis.

BACKGROUND: Progressive activation delay starting at long coupling intervals of premature stimuli has been shown to correlate with sudden cardiac death in patients with hypertrophic cardiomyopathy. The purpose of this study was to elucidate the mechanism of increased activation delay in chronically diseased myocardium. METHODS AND RESULTS: High-resolution unipolar mapping (105, 208, or 247 recording sites with interelectrode distances of 0.8, 0.5, or 0.3 mm, respectively) of epicardial electrical activity was carried out during premature stimulation in 11 explanted human hearts. The hearts came from patients who underwent heart transplantation and were in the end stage of heart failure (coronary artery disease, 4; hypertrophic cardiomyopathy, 1; and dilated cardiomyopathy, 6). Eight hearts were Langendorff-perfused. Epicardial sheets were taken from the remaining hearts and studied in a tissue bath. Activation maps and conduction curves were constructed and correlated with histology. Conduction curves revealing prominent increase of activation delay were associated with zones of dense, patchy fibrosis with long fibrotic strands. Dense, diffuse fibrosis with short fibrotic strands only marginally affected conduction curves. The course of conduction curves in patchy fibrotic areas greatly depended on the direction of propagation relative to fiber direction. CONCLUSIONS: The study demonstrates that in chronically diseased human myocardium, nonuniform anisotropic characteristics imposed by long fibrotic strands cause a progressive increase of activation delay, starting at long coupling intervals of premature stimuli. The increase strongly depends on the direction of the wave front with respect to fiber direction and the architecture of fibrosis.

Adult↗
PubMed2001

Cardio-aortic operation in octogenarians.

OBJECTIVE: Aging of the population is a current phenomenon in Japan, and life expectancy at 80 years old is getting longer. So we reviewed cardio-aortic operations on octogenarians at our institution. SUBJECTS AND METHODS: Thirty-three consecutive octogenarian patients who had undergone cardio-aortic operations from 1992 to 1998 were studied. There were 14 men and 19 women. The mean age was 81.9 years. Of the 33, 19 patients (58%) were in New York Heart Association class IV, and 21 patients (64%) were operated on urgently or in emergency. The procedures undergone were operation for coronary artery disease in 17 patients, operation for valvular disease in 7 patients, operation for thoracic-aorta in 7 patients, and others in 2 patients. RESULTS: The hospital mortality rate was 27% (9 patients). However, 89% of patients experiencing hospital death were in New York Heart Association class IV preoperatively and had required an emergency/urgent operation. On the other hand, there was only one hospital death (1/12, 8.3%) among the elective patients. The statistically significant risk factors for hospital death were renal insufficiency, shock, New York Heart Association class IV, intra-aortic balloon pumping, and longer cardiopulmonary bypass time. The one-, three-, and five-year-survival rate was 73%, 68%, and 55%, respectively. Of the survivors, 77% were in class I or II. CONCLUSION: Although octogenarians' hospital mortality was still very high, the mid-term results were acceptable and the survivors' quality of life was satisfactory. These data suggested that we should operate on cardio-aortic patients before they reach a very serious state, especially in octogenarians.

Age Factors↗
PubMed2001

Antiinflammatory effects of colforsin daropate hydrochloride, a novel water-soluble forskolin derivative.

BACKGROUND: To evaluate the effects of colforsin daropate hydrochloride (colforsin), a water-soluble forskolin derivative, on hemodynamics and systemic inflammatory response after cardiopulmonary bypass, we conducted a prospective randomized study. METHODS: Twenty-nine patients undergoing coronary artery bypass grafting were randomized to receive either colforsin treatment (colforsin; n = 14) or no colforsin treatment (control; n = 15). Administration of colforsin (0.5 microg.kg(-1).min(-1)) was started after induction of anesthesia and was continued for 6 hours. Perioperative cytokine and cyclic adenosine monophosphate levels, hemodynamics, and respiratory function were measured serially. RESULTS: Marked positive inotropic and vasodilatory effects were observed in patients receiving colforsin. Interleukin 1beta, interleukin 6, and interleukin 8 levels after cardiopulmonary bypass were significantly (p < 0.05) lower in the colforsin group. Plasma levels of cyclic adenosine monophosphate increased significantly (p < 0.05) in the colforsin group, and the levels correlated inversely (r = -0.56, p = 0.002) with the respiratory index after cardiopulmonary bypass. CONCLUSIONS: Intraoperative administration of colforsin daropate hydrochloride had potent inotropic and vasodilatory activity and attenuated cytokine production and respiratory dysfunction after cardiopulmonary bypass. The results indicate that the technique can be a novel therapeutic strategy for the systemic inflammatory response associated with cardiopulmonary bypass.

Aged↗
PubMed2001

Coronary artery bypass grafting in patients with mild renal insufficiency.

UNLABELLED: It is well known that dialysis-dependent renal failure increases the likelihood of a poor outcome following cardiac surgery. However, it is not known whether non-dialysis-dependent mild renal insufficiency also influences clinical outcome. Fifty-five patients with non-dialysis-dependent renal insufficiency undergoing coronary artery bypass grafting (CABG) (Renal group: serum creatinine level >1.5 mg/dl) were enrolled. These patients were then matched on prognostic variables to 148 patients with normal renal function ( CONTROL GROUP: serum creatinine level <1.5 mg/dl). The early postoperative clinical results showed that patients in the Renal group were more likely to develop postoperative renal failure (18% vs 1%: p=0.0002) and hemorrhage requiring re-exploration (11% vs 2%; p=0.01). Total morbidity was significantly higher in the Renal group (40% vs 22%; p=0.01). Multivariate analysis revealed that the Renal group was the second most important predictor of morbidity (odds ratio (OR) =2.2) behind left ventricular dysfunction (OR=2.9). The Renal group was also the second most important predictor of postoperative renal failure (OR=12.5). Therefore, non-dialysis-dependent mild renal insufficiency also increases the risk of morbidity following CABG.

Aged↗
PubMed2001

[Effects of colforsin daropate hydrochloride in patients undergoing coronary artery bypass surgery].

The effects of Adehl, colforsin daropate hydrochloride, on hemodynamics were studied in patients undergoing cardiac surgery. Twenty-six patients who underwent coronary artery bypass grafting were divided into two groups according to the intraoperative administration of Adehl. The control group (n = 14) received no Adehl treatment and the Adehl group (n = 12) received Adehl infusion immediately after anesthesia induction (0.5 microgram.kg-1.min-1) for 6 hours. Hemodynamic measurements and clinical results were accessed perioperatively. The Adehl group resulted in significantly (p < 0.05) lower pulmonary capillary wedge pressure and systemic vascular resistance, and significantly (p < 0.05) greater cardiac indices and left ventricular stroke work indices than those in the control group. No significant difference was found in the rate pressure product between the groups. The Adehl group resulted in significantly shorter duration of intubation and ICU stay. Adehl was not associated with a significant increase in the prevalence of adverse effects. The results suggest that Adehl has positive inotropic and vasodilator effects without increasing myocardial oxygen consumption. Thus, it is suggested that Adehl can be a useful agent for the perioperative management in patients undergoing cardiac surgery.

Aged↗
PubMed2001

Surgical treatment of prosthetic valve endocarditis with left ventricular-aortic discontinuity: reconstruction of the left ventricular outflow tract with a xenopericardial conduit.

BACKGROUND AND AIM OF THE STUDY: Aortic prosthetic valve endocarditis (PVE) with annular destruction presents a challenge that requires techniques to eradicate the infection and correct the hemodynamic abnormality. METHODS: Between July 1, 1996 and March 31, 2000, six patients with native or PVE of the aortic valve and aortic annular destruction underwent surgical treatment. Of these patients, three (two men, one woman; mean age 71.0 years) had circumferential annular destruction of the aortic annulus, and formed the basis of this study. The microorganisms responsible for the infection were Streptococcus spp. in two patients and Staphylococcus aureus in one patient. In addition to aggressive debridement of the infected tissue, repair was achieved by reconstruction of the left ventricular outflow tract with a xenopericardial conduit and fixation of the new prosthetic valve to the conduit. RESULTS: One patient with ventricular septal perforation, multiple systemic embolism and sepsis died of low cardiac output syndrome soon after surgery. Two operative survivors were followed up for 9 and 51 months, with no late deaths. No patient has experienced recurrent infection, pericardial patch aneurysm, or prosthetic valve detachment. CONCLUSION: These operative procedures provide easy and secure fixation of the pericardial patch to the healthy tissue under excellent operative view, as well as a sturdy structure for the fixation of the new prosthesis, and complete exclusion of the abscess cavity from the blood stream.

Aged↗
PubMed2001

Influence of renal function on serum and urinary heart fatty acid-binding protein levels.

BACKGROUND: Serum heart fatty acid-binding protein (H-FABP) has been reported to be a sensitive and early indicator of myocardial damage. However, circulating H-FABP may be cleared considerably from kidney, similar to that found for myoglobin. Therefore, the possibility exists that any change in renal function affects serum H-FABP concentration, and thus leads to erroneous interpretation. To evaluate the influence of renal function on H-FABP levels, we conducted a prospective study. METHODS: Nineteen patients undergoing isolated primary coronary artery bypass grafting were enrolled in this study. The patients were classified by the preoperative creatinine clearance into two groups: the control group (n=12); patients with creatinine clearance of 40 mL/min or greater, and the renal dysfunction group (n=7); patients with creatinine clearance of less than 40 mL/min. Serum H-FABP, CK-MB, troponin-T and urinary H-FABP levels were measured perioperatively. RESULTS: None of the patients had perioperative myocardial infarction. No significant differences were found in CK-MB and troponin-T levels between the groups. The renal dysfunction group resulted in significantly (p<0.05) higher serum H-FABP levels and lower urinary H-FABP levels than those in the control group, postoperatively. The creatinine clearance correlated inversely with the peak levels of serum H-FABP (r=-0.75, p=0.0001) and correlated with the peak levels of urinary H-FABP (r=0.64, p=0.003). CONCLUSIONS: The results indicate that the kidneys play an important role in the clearance of serum H-FABP. Thus, caution must be taken in interpreting this marker for myocardial damage during cardiac surgery in patients with renal dysfunction.

Aged↗
PubMed2001

Open heart operation in a patient with hereditary spherocytosis: a case report.

A 9-year-old girl who had ostium secundum atrial septal defect (ASD) and hereditary spherocytosis (HS) is described. The patient had a history of splenectomy for HS and underwent repair of the ASD under cardiopulmonary bypass (CPB), however, no significant or persistent hemolysis was observed during and after CPB. Only 10 patients with HS who underwent cardiac operations using CPB have been reported. The case is presented due to its rarity.

Cardiopulmonary Bypass↗
PubMed2000

Surgical treatment for graft stenosis after repair of an interrupted aortic arch: report of two cases.

We report herein two cases of patients who underwent successful reoperation for graft stenosis after repair of an interrupted aortic arch (IAA). The first patient was a 10-year-old girl who suffered from upper limb hypertension 9 years after her initial operation. Cardiac catheterization revealed a pressure gradient of 55 mmHg across the repaired arch. At reoperation, a left subclavian turndown anastomosis was performed, following which the hypertension resolved and a cardiac catheterization done 5 years later demonstrated sufficient growth of the restored arch with no significant gradient. The second patient was a 17-year-old boy who suffered from general fatigue and intermittent hypertension 12 years after his initial operation. Cardiac catheterization revealed a gradient of 60 mmHg across the repaired arch. He underwent an extraanatomic ascending to descending aortic bypass employing an additional 18-mm graft, and a postoperative cardiac catheterization showed no gradient between the ascending and descending aorta. Our experience has shown that IAA should be repaired without prosthetic grafts if possible. Although extraanatomic bypass is useful for reducing the operative risks at reoperation, a large graft should be used to avoid the need for a third operation. For young children expected to outgrow a second graft, performing an endogenous anastomosis, such as a left subclavian turndown anastomosis, should be considered as an alternative.

Adolescent↗
PubMed2000

Marked anterograde decremental conduction over a rapidly conducting accessory pathway after radiofrequency ablation.

We report on a patient with the Wolff-Parkinson-White syndrome who temporarily exhibited a marked anterograde decremental conduction over a rapidly conducting accessory atrioventricular pathway after successful radiofrequency ablation. By recording the intracardiac electrogram via the ablation catheter placed at the successful ablation site, we were able to exclude the possibility of the occurrence of anterograde decremental conduction in the atrial or ventricular myocardium between the accessory pathway and the recording electrodes.

Catheter Ablation↗
PubMed2000

Tricuspid valve replacement with the St. Jude Medical valve: 19 years of experience.

OBJECTIVE: The choice of the valve substitute in the tricuspid position remains controversial. A St. Jude Medical valve is a choice of valve substitute and its lower thrombogenicity and excellent hemodynamic performance have been reported even in the tricuspid position. However, little is known of the long-term durability of the St. Jude Medical valve in the tricuspid position. Our long-term experience of tricuspid valve replacement showed the higher thrombogenicity than we had expected, therefore, this study was done to reconsider our strategy for valve choice. METHODS: This study reviewed 23 patient who underwent 25 tricuspid valve replacements with the St. Jude Medical valves from 1980 to 1997. The mean age was 40 years. Eleven patients (48%) were men. There were four in-hospital deaths (17%). The remaining 19 patients were all alive and followed from 2.2 to 19.0 years (mean 11.8 years). RESULTS: The overall survival, including hospital mortality, was 83%, 10 and 15 years after surgery. Valve thrombosis occurred in six patients. Freedom from valve thrombosis was 78 and 70%, 10 and 15 years after surgery, respectively. The linearized rate of the valve thrombosis was 2.9%/patient-years. Six patients required reoperation. The mean interval to reoperation was 9.5 years. Freedom from reoperation was 83% and 75%, 10 and 15 years after surgery, respectively. The linearized rate of the reoperation was 2.8%/patient-years. No structural valve deterioration was found. Echocardiographic study showed that the function of the St. Jude Medical valve without valve-related complications was well maintained. CONCLUSIONS: The higher thrombogenicity of the St. Jude Medical valve in the tricuspid position altered our choice of valve substitutes from the St. Jude Medical valve to a bioprosthesis which is lack of need for anticoagulant therapy except for juvenile patients who are able to maintain potent anticoagulant therapy.

Adolescent↗
PubMed2000

Biocompatibility of heparin-coated extracorporeal bypass circuits: new heparin bonded bioline system.

Biocompatibility of a new type of heparin-coated cardiopulmonary bypass equipment, the Bioline, was evaluated in coronary artery bypass surgery cases. The heparin-coated (H) group (n = 15; Quadrox Bioline oxygenator/reservior and Carmeda BioMedicus BP-80 centrifugal pump) was compared with the nonheparin-coated (N) group (n = 12; uncoated, otherwise similar oxygenator, centrifugal pump, tubing, and filter set). Both groups used full systemic heparinization. The peak values of neutrophil elastase, C3a, IL-6, and IL-8 at 2 h after cardiopulmonary bypass (CPB), and C3a levels at the end of CPB and at 2 h after CPB were significantly reduced in the H group compared with those of the N group. However, no statistically significant intergroup differences were observed in thrombin-antithrombin complex, D-dimer, beta-thromboglobulin, or platelet factor-4. No significant differences were observed in hemostasis time, postoperative 12 h blood loss, required amount of blood transfusion, or intubation time. In conclusion, the Bioline demonstrated partially improved biocompatibility, in terms of leukocyte and complement activation, and proinflammatory cytokine production. However, it did not improve platelet activation, coagulation, or fibrinolysis cascade under full systemic heparinization. As a result, the clinical beneficial impact seemed to be the minimum.

Aged↗
PubMed2000

Obstruction of St Jude Medical valves in the aortic position: significance of a combination of cineradiography and echocardiography.

BACKGROUND: Obstruction of the St Jude Medical valve (St Jude Medical, Inc, St Paul, Minn) is a rare but serious complication. METHODS: Cineradiographic and echocardiographic evaluations of aortic St Jude Medical valves were simultaneously performed on 54 patients, with no signs of prosthetic valve dysfunction late after surgery. RESULTS: Although closing angles of the leaflets corresponded closely with the manufacturer data, restricted opening of the leaflets (opening angle >/= 20 degrees ) was found in 16 (group D) of the 54 patients by means of cineradiography. The opening angles were equal to or less than 14 degrees in the other 23 patients (group N) and between 15 degrees and 19 degrees in the remaining 15 (group M). Doppler-derived transprosthetic pressure gradients were significantly higher (P =.03) and the velocity index was significantly lower (P =.003) in group D than in group N. However, no significant differences were found in those values between group N and group M. Replacement of the aortic St Jude Medical valves was performed in 5 of the 16 patients, and the remaining 11 have been followed up because of relatively low pressure gradients. The cause of restricted leaflet movement was pannus formation without thrombosis in 4 patients and valve thrombosis with pannus formation in one. CONCLUSIONS: Reduced valve orifice area and restricted opening of the leaflets resulting from excess growth of pannus probably led to obstruction of the aortic St Jude Medical valves. A combination of cineradiography and echocardiography makes it possible to provide an accurate and detailed diagnosis of obstruction of the valve.

Adolescent↗
PubMed2000

Augmentation of QRS wave amplitudes in the precordial leads during narrow QRS tachycardia.

INTRODUCTION: QRS morphology during narrow QRS supraventricular tachycardia in patients without ventricular preexcitation generally is considered the same as that seen during sinus rhythm. This study presents a new ECG observation that the QRS amplitude increased significantly in leads V2 through V5 during tachycardia. METHODS AND RESULTS: Using the same ECG machine and the same electrode patches applied to the same electrode positions, 12-lead ECGs during sinus rhythm and narrow QRS tachycardia were analyzed comparatively in 23 patients without ventricular preexcitation. Precordial QRS amplitudes were measured as the vertical distance from the peak of the R to the nadir of the S wave. The amplitudes also were measured during atrial rapid pacing and extrastimulation. Furthermore, ventricular excitation during sinus rhythm and tachycardia was studied using body surface mapping. Body surface distributions of QRS potentials and ventricular activation time (VAT) were displayed as maps. Gross area of QRS (AQRS, equivalent to the QRS amplitude) was compared during sinus rhythm versus tachycardia. During tachycardia, QRS amplitude significantly increased in leads V2 through V5, without any noticeable change in the transitional zone or QRS wave duration. Increase of QRS amplitude also was noted during atrial rapid pacing and extrastimulation. Gross AQRS values during tachycardia significantly increased in the left parasternal area, whereas QRS isopotential and VAT isochronal maps were similar during sinus rhythm and tachycardia, suggesting a minimal role of conduction delay in the increase of QRS amplitude. CONCLUSION: QRS wave amplitude significantly increased in leads V2 through V5 during narrow QRS tachycardia compared with QRS waves in sinus rhythm. Increase of QRS amplitude seemed unlikely due to a conduction delay within the ventricular myocardium.

Adolescent↗
PubMed2000

Demonstration of phase-3 and phase-4 retrograde block in a second concealed accessory pathway after an initial successful radiofrequency ablation of a 'normal' concealed accessory pathway.

We report a patient with concealed Wolff-Parkinson-White syndrome who, following catheter ablation, demonstrated phase-3 and phase-4 retrograde block in a concealed accessory pathway. After an initial 'apparently successful' ablation, retrograde conduction was through the atrioventricular node during constant ventricular pacing. Ventricular extrastimulus testing was performed at a basic drive cycle length of 600 ms. Unexpectedly, ventricular extrastimuli at coupling intervals of 440-380 ms were conducted retrogradely over an accessory pathway, consistent with a phase-3 and phase-4 retrograde block in the accessory pathway. Residual accessory pathway conduction was eliminated in a single ablation session.

Catheter Ablation↗
PubMed2000

Plasma and urinary levels of heart fatty acid-binding protein in patients undergoing cardiac surgery.

To evaluate the clinical significance of the plasma and urinary levels of heart fatty acid-binding protein (H-FABP) in patients undergoing cardiac surgery, a prospective study was conducted. Ten patients undergoing coronary artery bypass grafting were enrolled. Blood samples for determination of plasma H-FABP (pH-FABP), the MB isoenzyme of creatine kinase (CK-MB) and troponin-T (TnT), and urine samples for determination of urinary H-FABP (uH-FABP) were collected serially. None of the patients had perioperative myocardial infarction. The time to reach the peak level after aortic declamping was significantly (p<0.05) shorter for pH-FABP (1.4+/-0.5 h) than for CK-MB (2.5+/-0.5 h), TnT (6.6+/-1.3 h) or uH-FABP (3.0+/-0.6 h). Peak levels of pH-FABP correlated with those of CK-MB (r = 0.51, p = 0.04), TnT (r = 0.60, p = 0.03) and uH-FABP (r = 0.61, p = 0.03), and peak levels of uH-FABP correlated with CK-MB (r = 0.57, p = 0.04). Postoperative uH-FABP levels correlated inversely with the left ventricular stroke work index (r = -0.63, p = 0.04). This study demonstrated that H-FABP appears rapidly in plasma after reperfusion and reaches its peak earlier than other available biochemical markers; it appears also in urine and the levels correlated with cardiac function. Plasma and urinary H-FABP may be an early and sensitive biochemical marker for the diagnosis of myocardial injury in patients undergoing cardiac surgery.

Blood Pressure↗
PubMed2000

Coronary artery bypass surgery in a patient with myasthenia gravis.

A 73-year-old man with myasthenia gravis required quadruple coronary artery bypass grafting due to triple-vessel disease. Anesthetic management was performed with general anesthesia using a reduced dose of muscle relaxant with the aid of a neuromuscular transmission monitor. He was extubated 14 hrs after surgery without difficulty under this monitor. His postoperative course was uneventful. A patient with myasthenia gravis who required coronary artery bypass surgery was successfully performed by the deliberate preoperative evaluation of patient's myasthenic and cardiac status, and by the careful perioperative management.

Aged↗